Chain of custody for enterprise documents

ABSTRACT

A ledger stores chain of custody information for files throughout an enterprise network. By identifying files with a homologous identifier such as a fuzzy hash that permits piecewise evaluation of similarity, the ledger can be used to track a chain of custody over a sequence of changes in content, ownership, and file properties. The ledger can be used, e.g., to evaluate trustworthiness of a file the first time it is encountered by an endpoint, or to apply enterprise policies based on trust.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No. 62/744,956 filed on Oct. 12, 2018, the entire contents of which is hereby incorporated by reference.

FIELD

The present disclosure generally relates to a threat management system.

BACKGROUND

There remains a need for improved threat management systems.

SUMMARY

A ledger stores chain of custody information for files throughout an enterprise network. By identifying files with a homologous identifier such as a fuzzy hash that permits piecewise evaluation of similarity, the ledger can be used to track a chain of custody over a sequence of changes in content, ownership, and file properties. The ledger can be used, e.g., to evaluate trustworthiness of a file the first time it is encountered by an endpoint, or to apply enterprise policies based on trust.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the devices, systems, and methods described herein will be apparent from the following description of particular embodiments thereof, as illustrated in the accompanying drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the devices, systems, and methods described herein.

FIG. 1 depicts a block diagram of a threat management system.

FIG. 2 depicts a block diagram of a threat management system.

FIG. 3 depicts an asset classification facility and an enterprise facility.

FIG. 4 depicts a sensors, events, enforcement, and response (SEER) environment.

FIG. 5 depicts centralized event collection.

FIG. 6 depicts dynamic evaluation and authentication.

FIG. 7 depicts a marketplace interface facility.

FIG. 8 depicts a flowchart of a method for data loss prevention.

FIG. 9 shows a flowchart of a method for threat detection with business impact scoring.

FIG. 10 shows a block diagram of a system for enterprise document classification.

FIG. 11 shows a flowchart of a method for enterprise document classification.

FIG. 12 shows a block diagram of a system for managing chain of custody for enterprise documents.

FIG. 13 shows a method for managing chain of custody for documents in an enterprise network.

DESCRIPTION

Embodiments will now be described with reference to the accompanying figures. The foregoing may, however, be embodied in many different forms and should not be construed as limited to the illustrated embodiments set forth herein.

All documents mentioned herein are hereby incorporated by reference in their entirety. References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context. Thus, the term “or” should generally be understood to mean “and/or” and so forth.

Recitation of ranges of values herein are not intended to be limiting, referring instead individually to any and all values falling within the range, unless otherwise indicated herein, and each separate value within such a range is incorporated into the specification as if it were individually recited herein. The words “about,” “approximately” or the like, when accompanying a numerical value, are to be construed as indicating a deviation as would be appreciated by one of ordinary skill in the art to operate satisfactorily for an intended purpose. Similarly, words of approximation such as “approximately” or “substantially” when used in reference to physical characteristics, should be understood to contemplate a range of deviations that would be appreciated by one of ordinary skill in the art to operate satisfactorily for a corresponding use, function, purpose, or the like. Ranges of values and/or numeric values are provided herein as examples only, and do not constitute a limitation on the scope of the described embodiments. Where ranges of values are provided, they are also intended to include each value within the range as if set forth individually, unless expressly stated to the contrary. The use of any and all examples, or exemplary language (“e.g.,” “such as,” or the like) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the embodiments. No language in the specification should be construed as indicating any unclaimed element as essential to the practice of the embodiments.

In the following description, it is understood that terms such as “first,” “second,” “top,” “bottom,” “up,” “down,” and the like, are words of convenience and are not to be construed as limiting terms.

As described herein, a threat management system may use a Sensor, Events, Analytics, and Response (SEAR) approach to protect enterprises against cybersecurity threats.

FIG. 1 depicts a block diagram of a threat management system 101 providing protection against a plurality of threats, such as malware, viruses, spyware, cryptoware, adware, Trojans, spam, intrusion, policy abuse, improper configuration, vulnerabilities, improper access, uncontrolled access, and more. A threat management facility 100 may communicate with, coordinate, and control operation of security functionality at different control points, layers, and levels within the system 101. A number of capabilities may be provided by a threat management facility 100, with an overall goal to intelligently use the breadth and depth of information that is available about the operation and activity of compute instances and networks as well as a variety of available controls. Another overall goal is to provide protection needed by an organization that is dynamic and able to adapt to changes in compute instances and new threats. In embodiments, the threat management facility 100 may provide protection from a variety of threats to a variety of compute instances in a variety of locations and network configurations.

Just as one example, users of the threat management facility 100 may define and enforce policies that control access to and use of compute instances, networks and data. Administrators may update policies such as by designating authorized users and conditions for use and access. The threat management facility 100 may update and enforce those policies at various levels of control that are available, such as by directing compute instances to control the network traffic that is allowed to traverse firewalls and wireless access points, applications and data available from servers, applications and data permitted to be accessed by endpoints, and network resources and data permitted to be run and used by endpoints. The threat management facility 100 may provide many different services, and policy management may be offered as one of the services.

Turning to a description of certain capabilities and components of the threat management system 101, an exemplary enterprise facility 102 may be or may include any networked computer-based infrastructure. For example, the enterprise facility 102 may be corporate, commercial, organizational, educational, governmental, or the like. As home networks get more complicated, and include more compute instances at home and in the cloud, an enterprise facility 102 may also or instead include a personal network such as a home or a group of homes. The enterprise facility's 102 computer network may be distributed amongst a plurality of physical premises such as buildings on a campus, and located in one or in a plurality of geographical locations. The configuration of the enterprise facility as shown is merely exemplary, and it will be understood that there may be any number of compute instances, less or more of each type of compute instances, and other types of compute instances. As shown, the exemplary enterprise facility includes a firewall 10, a wireless access point 11, an endpoint 12, a server 14, a mobile device 16, an appliance or TOT device 18, a cloud computing instance 19, and a server 20. Again, the compute instances 10-20 depicted are exemplary, and there may be any number or types of compute instances 10-20 in a given enterprise facility. For example, in addition to the elements depicted in the enterprise facility 102, there may be one or more gateways, bridges, wired networks, wireless networks, virtual private networks, other compute instances, and so on.

The threat management facility 100 may include certain facilities, such as a policy management facility 112, security management facility 122, update facility 120, definitions facility 114, network access rules facility 124, remedial action facility 128, detection techniques facility 130, application protection facility 150, asset classification facility 160, entity model facility 162, event collection facility 164, event logging facility 166, analytics facility 168, dynamic policies facility 170, identity management facility 172, and marketplace management facility 174, as well as other facilities. For example, there may be a testing facility, a threat research facility, and other facilities. It should be understood that the threat management facility 100 may be implemented in whole or in part on a number of different compute instances, with some parts of the threat management facility on different compute instances in different locations. For example, some or all of one or more of the various facilities 100, 112-174 may be provided as part of a security agent S that is included in software running on a compute instance 10-26 within the enterprise facility. Some or all of one or more of the facilities 100, 112-174 may be provided on the same physical hardware or logical resource as a gateway, such as a firewall 10, or wireless access point 11. Some or all of one or more of the facilities may be provided on one or more cloud servers that are operated by the enterprise or by a security service provider, such as the cloud computing instance 109.

In embodiments, a marketplace provider 199 may make available one or more additional facilities to the enterprise facility 102 via the threat management facility 100. The marketplace provider may communicate with the threat management facility 100 via the marketplace interface facility 174 to provide additional functionality or capabilities to the threat management facility 100 and compute instances 10-26. A marketplace provider 199 may be selected from a number of providers in a marketplace of providers that are available for integration or collaboration via the marketplace interface facility 174. A given marketplace provider 199 may use the marketplace interface facility 174 even if not engaged or enabled from or in a marketplace. As non-limiting examples, the marketplace provider 199 may be a third-party information provider, such as a physical security event provider; the marketplace provider 199 may be a system provider, such as a human resources system provider or a fraud detection system provider; the marketplace provider 199 may be a specialized analytics provider; and so on. The marketplace provider 199, with appropriate permissions and authorization, may receive and send events, observations, inferences, controls, convictions, policy violations, or other information to the threat management facility. For example, the marketplace provider 199 may subscribe to and receive certain events, and in response, based on the received events and other events available to the marketplace provider 199, send inferences to the marketplace interface, and in turn to the analytics facility 168, which in turn may be used by the security management facility 122.

The identity provider 158 may be any remote identity management system or the like configured to communicate with an identity management facility 172, e.g., to confirm identity of a user as well as provide or receive other information about users that may be useful to protect against threats. In general, the identity provider may be any system or entity that creates, maintains, and manages identity information for principals while providing authentication services to relying party applications, e.g., within a federation or distributed network. The identity provider may, for example, offer user authentication as a service, where other applications, such as web applications, outsource the user authentication step to a trusted identity provider.

In embodiments, the identity provider 158 may provide user identity information, such as multi-factor authentication, to a SaaS application. Centralized identity providers such as Microsoft Azure, may be used by an enterprise facility instead of maintaining separate identity information for each application or group of applications, and as a centralized point for integrating multifactor authentication. In embodiments, the identity management facility 172 may communicate hygiene, or security risk information, to the identity provider 158. The identity management facility 172 may determine a risk score for a user based on the events, observations, and inferences about that user and the compute instances associated with the user. If a user is perceived as risky, the identity management facility 172 can inform the identity provider 158, and the identity provider 158 may take steps to address the potential risk, such as to confirm the identity of the user, confirm that the user has approved the SaaS application access, remediate the user's system, or such other steps as may be useful.

In embodiments, threat protection provided by the threat management facility 100 may extend beyond the network boundaries of the enterprise facility 102 to include clients (or client facilities) such as an endpoint 22 outside the enterprise facility 102, a mobile device 26, a cloud computing instance 109, or any other devices, services or the like that use network connectivity not directly associated with or controlled by the enterprise facility 102, such as a mobile network, a public cloud network, or a wireless network at a hotel or coffee shop. While threats may come from a variety of sources, such as from network threats, physical proximity threats, secondary location threats, the compute instances 10-26 may be protected from threats even when a compute instance 10-26 is not connected to the enterprise facility 102 network, such as when compute instances 22, 26 use a network that is outside of the enterprise facility 102 and separated from the enterprise facility 102, e.g., by a gateway, a public network, and so forth.

In some implementations, compute instances 10-26 may communicate with cloud applications, such as a SaaS application 156. The SaaS application 156 may be an application that is used by but not operated by the enterprise facility 102. Exemplary commercially available SaaS applications 156 include Salesforce, Amazon Web Services (AWS) applications, Google Apps applications, Microsoft Office 365 applications and so on. A given SaaS application 156 may communicate with an identity provider 158 to verify user identity consistent with the requirements of the enterprise facility 102. The compute instances 10-26 may communicate with an unprotected server (not shown) such as a web site or a third-party application through an internetwork 154 such as the Internet or any other public network, private network or combination of these.

In embodiments, aspects of the threat management facility 100 may be provided as a stand-alone solution. In other embodiments, aspects of the threat management facility 100 may be integrated into a third-party product. An application programming interface (e.g. a source code interface) may be provided such that aspects of the threat management facility 100 may be integrated into or used by or with other applications. For instance, the threat management facility 100 may be stand-alone in that it provides direct threat protection to an enterprise or computer resource, where protection is subscribed to directly 100. Alternatively, the threat management facility may offer protection indirectly, through a third-party product, where an enterprise may subscribe to services through the third-party product, and threat protection to the enterprise may be provided by the threat management facility 100 through the third-party product.

The security management facility 122 may provide protection from a variety of threats by providing, as non-limiting examples, endpoint security and control, email security and control, web security and control, reputation-based filtering, machine learning classification, control of unauthorized users, control of guest and non-compliant computers, and more.

The security management facility 122 may provide malicious code protection to a compute instance. The security management facility 122 may include functionality to scan applications, files, and data for malicious code, remove or quarantine applications and files, prevent certain actions, perform remedial actions, as well as other security measures. Scanning may use any of a variety of techniques, including without limitation signatures, identities, classifiers, and other suitable scanning techniques. In embodiments, the scanning may include scanning some or all files on a periodic basis, scanning an application when the application is executed, scanning data transmitted to or from a device, scanning in response to predetermined actions or combinations of actions, and so forth. The scanning of applications, files, and data may be performed to detect known or unknown malicious code or unwanted applications. Aspects of the malicious code protection may be provided, for example, in the security agent of an endpoint 12, in a wireless access point 11 or firewall 10, as part of application protection 150 provided by the cloud, and so on.

In an embodiment, the security management facility 122 may provide for email security and control, for example to target spam, viruses, spyware and phishing, to control email content, and the like. Email security and control may protect against inbound and outbound threats, protect email infrastructure, prevent data leakage, provide spam filtering, and more. Aspects of the email security and control may be provided, for example, in the security agent of an endpoint 12, in a wireless access point 11 or firewall 10, as part of application protection 150 provided by the cloud, and so on.

In an embodiment, security management facility 122 may provide for web security and control, for example, to detect or block viruses, spyware, malware, unwanted applications, help control web browsing, and the like, which may provide comprehensive web access control enabling safe, productive web browsing. Web security and control may provide Internet use policies, reporting on suspect compute instances, security and content filtering, active monitoring of network traffic, URI filtering, and the like. Aspects of the web security and control may be provided, for example, in the security agent of an endpoint 12, in a wireless access point 11 or firewall 10, as part of application protection 150 provided by the cloud, and so on.

In an embodiment, the security management facility 122 may provide for network access control, which generally controls access to and use of network connections. Network control may stop unauthorized, guest, or non-compliant systems from accessing networks, and may control network traffic that is not otherwise controlled at the client level. In addition, network access control may control access to virtual private networks (VPN), where VPNs may, for example, include communications networks tunneled through other networks and establishing logical connections acting as virtual networks. In embodiments, a VPN may be treated in the same manner as a physical network. Aspects of network access control may be provided, for example, in the security agent of an endpoint 12, in a wireless access point 11 or firewall 10, as part of application protection 150 provided by the cloud, e.g., from the threat management facility 100 or other network resource(s).

In an embodiment, the security management facility 122 may provide for host intrusion prevention through behavioral monitoring and/or runtime monitoring, which may guard against unknown threats by analyzing application behavior before or as an application runs. This may include monitoring code behavior, application programming interface calls made to libraries or to the operating system, or otherwise monitoring application activities. Monitored activities may include, for example, reading and writing to memory, reading and writing to disk, network communication, process interaction, and so on. Behavior and runtime monitoring may intervene if code is deemed to be acting in a manner that is suspicious or malicious. Aspects of behavior and runtime monitoring may be provided, for example, in the security agent of an endpoint 12, in a wireless access point 11 or firewall 10, as part of application protection 150 provided by the cloud, and so on.

In an embodiment, the security management facility 122 may provide for reputation filtering, which may target or identify sources of known malware. For instance, reputation filtering may include lists of URIs of known sources of malware or known suspicious IP addresses, code authors, code signers, or domains, that when detected may invoke an action by the threat management facility 100. Based on reputation, potential threat sources may be blocked, quarantined, restricted, monitored, or some combination of these, before an exchange of data can be made. Aspects of reputation filtering may be provided, for example, in the security agent of an endpoint 12, in a wireless access point 11 or firewall 10, as part of application protection 150 provided by the cloud, and so on. In embodiments, some reputation information may be stored on a compute instance 10-26, and other reputation data available through cloud lookups to an application protection lookup database, such as may be provided by application protection 150.

In embodiments, information may be sent from the enterprise facility 102 to a third party, such as a security vendor, or the like, which may lead to improved performance of the threat management facility 100. In general, feedback may be useful for any aspect of threat detection. For example, the types, times, and number of virus interactions that an enterprise facility 102 experiences may provide useful information for the preventions of future virus threats. Feedback may also be associated with behaviors of individuals within the enterprise, such as being associated with most common violations of policy, network access, unauthorized application loading, unauthorized external device use, and the like. In embodiments, feedback may enable the evaluation or profiling of client actions that are violations of policy that may provide a predictive model for the improvement of enterprise policies.

An update management facility 120 may provide control over when updates are performed. The updates may be automatically transmitted, manually transmitted, or some combination of these. Updates may include software, definitions, reputations or other code or data that may be useful to the various facilities. For example, the update facility 120 may manage receiving updates from a provider, distribution of updates to enterprise facility 102 networks and compute instances, or the like. In embodiments, updates may be provided to the enterprise facility's 102 network, where one or more compute instances on the enterprise facility's 102 network may distribute updates to other compute instances.

The threat management facility 100 may include a policy management facility 112 that manages rules or policies for the enterprise facility 102. Exemplary rules include access permissions associated with networks, applications, compute instances, users, content, data, and the like. The policy management facility 112 may use a database, a text file, other data store, or a combination to store policies. In an embodiment, a policy database may include a block list, a black list, an allowed list, a white list, and more. As a few non-limiting examples, policies may include a list of enterprise facility 102 external network locations/applications that may or may not be accessed by compute instances, a list of types/classifications of network locations or applications that may or may not be accessed by compute instances, and contextual rules to evaluate whether the lists apply. For example, there may be a rule that does not permit access to sporting websites. When a website is requested by the client facility, a security management facility 122 may access the rules within a policy facility to determine if the requested access is related to a sporting website.

The policy management facility 112 may include access rules and policies that are distributed to maintain control of access by the compute instances 10-26 to network resources. Exemplary policies may be defined for an enterprise facility, application type, subset of application capabilities, organization hierarchy, compute instance type, user type, network location, time of day, connection type, or any other suitable definition. Policies may be maintained through the threat management facility 100, in association with a third party, or the like. For example, a policy may restrict instant messaging (IM) activity by limiting such activity to support personnel when communicating with customers. More generally, this may allow communication for departments as necessary or helpful for department functions, but may otherwise preserve network bandwidth for other activities by restricting the use of IM to personnel that need access for a specific purpose. In an embodiment, the policy management facility 112 may be a stand-alone application, may be part of the network server facility 142, may be part of the enterprise facility 102 network, may be part of the client facility, or any suitable combination of these.

The policy management facility 112 may include dynamic policies that use contextual or other information to make security decisions. As described herein, the dynamic policies facility 170 may generate policies dynamically based on observations and inferences made by the analytics facility. The dynamic policies generated by the dynamic policy facility 170 may be provided by the policy management facility 112 to the security management facility 122 for enforcement.

In embodiments, the threat management facility 100 may provide configuration management as an aspect of the policy management facility 112, the security management facility 122, or some combination. Configuration management may define acceptable or required configurations for the compute instances 10-26, applications, operating systems, hardware, or other assets, and manage changes to these configurations. Assessment of a configuration may be made against standard configuration policies, detection of configuration changes, remediation of improper configurations, application of new configurations, and so on. An enterprise facility may have a set of standard configuration rules and policies for particular compute instances which may represent a desired state of the compute instance. For example, on a given compute instance 12, 14, 18, a version of a client firewall may be required to be running and installed. If the required version is installed but in a disabled state, the policy violation may prevent access to data or network resources. A remediation may be to enable the firewall. In another example, a configuration policy may disallow the use of USB disks, and policy management 112 may require a configuration that turns off USB drive access via a registry key of a compute instance. Aspects of configuration management may be provided, for example, in the security agent of an endpoint 12, in a wireless access point 11 or firewall 10, as part of application protection 150 provided by the cloud, or any combination of these.

In embodiments, the threat management facility 100 may also provide for the isolation or removal of certain applications that are not desired or may interfere with the operation of a compute instance 10-26 or the threat management facility 100, even if such application is not malware per se. The operation of such products may be considered a configuration violation. The removal of such products may be initiated automatically whenever such products are detected, or access to data and network resources may be restricted when they are installed and running. In the case where such applications are services which are provided indirectly through a third-party product, the applicable application or processes may be suspended until action is taken to remove or disable the third-party product.

The policy management facility 112 may also require update management (e.g., as provided by the update facility 120). Update management for the security facility 122 and policy management facility 112 may be provided directly by the threat management facility 100, or, for example, by a hosted system. In embodiments, the threat management facility 100 may also provide for patch management, where a patch may be an update to an operating system, an application, a system tool, or the like, where one of the reasons for the patch is to reduce vulnerability to threats.

In embodiments, the security facility 122 and policy management facility 112 may push information to the enterprise facility 102 network and/or the compute instances 10-26, the enterprise facility 102 network and/or compute instances 10-26 may pull information from the security facility 122 and policy management facility 112, or there may be a combination of pushing and pulling of information. For example, the enterprise facility 102 network and/or compute instances 10-26 may pull update information from the security facility 122 and policy management facility 112 via the update facility 120, an update request may be based on a time period, by a certain time, by a date, on demand, or the like. In another example, the security facility 122 and policy management facility 112 may push the information to the enterprise facility's 102 network and/or compute instances 10-26 by providing notification that there are updates available for download and/or transmitting the information. In an embodiment, the policy management facility 112 and the security facility 122 may work in concert with the update management facility 120 to provide information to the enterprise facility's 102 network and/or compute instances 10-26. In various embodiments, policy updates, security updates and other updates may be provided by the same or different modules, which may be the same or separate from a security agent running on one of the compute instances 10-26.

As threats are identified and characterized, the definition facility 114 of the threat management facility 100 may manage definitions used to detect and remediate threats. For example, identity definitions may be used for scanning files, applications, data streams, etc. for the determination of malicious code. Identity definitions may include instructions and data that can be parsed and acted upon for recognizing features of known or potentially malicious code. Definitions also may include, for example, code or data to be used in a classifier, such as a neural network or other classifier that may be trained using machine learning. Updated code or data may be used by the classifier to classify threats. In embodiments, the threat management facility 100 and the compute instances 10-26 may be provided with new definitions periodically to include most recent threats. Updating of definitions may be managed by the update facility 120, and may be performed upon request from one of the compute instances 10-26, upon a push, or some combination. Updates may be performed upon a time period, on demand from a device 10-26, upon determination of an important new definition or a number of definitions, and so on.

A threat research facility (not shown) may provide a continuously ongoing effort to maintain the threat protection capabilities of the threat management facility 100 in light of continuous generation of new or evolved forms of malware. Threat research may be provided by researchers and analysts working on known threats, in the form of policies, definitions, remedial actions, and so on.

The security management facility 122 may scan an outgoing file and verify that the outgoing file is permitted to be transmitted according to policies. By checking outgoing files, the security management facility 122 may be able discover threats that were not detected on one of the compute instances 10-26, or policy violation, such transmittal of information that should not be communicated unencrypted.

The threat management facility 100 may control access to the enterprise facility 102 networks. A network access facility 124 may restrict access to certain applications, networks, files, printers, servers, databases, and so on. In addition, the network access facility 124 may restrict user access under certain conditions, such as the user's location, usage history, need to know, job position, connection type, time of day, method of authentication, client-system configuration, or the like. Network access policies may be provided by the policy management facility 112, and may be developed by the enterprise facility 102, or pre-packaged by a supplier. Network access facility 124 may determine if a given compute instance 10-22 should be granted access to a requested network location, e.g., inside or outside of the enterprise facility 102. Network access facility 124 may determine if a compute instance 22, 26 such as a device outside the enterprise facility 102 may access the enterprise facility 102. For example, in some cases, the policies may require that when certain policy violations are detected, certain network access is denied. The network access facility 124 may communicate remedial actions that are necessary or helpful to bring a device back into compliance with policy as described below with respect to the remedial action facility 128. Aspects of the network access facility 124 may be provided, for example, in the security agent of the endpoint 12, in a wireless access point 11, in a firewall 10, as part of application protection 150 provided by the cloud, and so on.

In an embodiment, the network access facility 124 may have access to policies that include one or more of a block list, a black list, an allowed list, a white list, an unacceptable network site database, an acceptable network site database, a network site reputation database, or the like of network access locations that may or may not be accessed by the client facility. Additionally, the network access facility 124 may use rule evaluation to parse network access requests and apply policies. The network access rule facility 124 may have a generic set of policies for all compute instances, such as denying access to certain types of websites, controlling instant messenger accesses, or the like. Rule evaluation may include regular expression rule evaluation, or other rule evaluation method(s) for interpreting the network access request and comparing the interpretation to established rules for network access. Classifiers may be used, such as neural network classifiers or other classifiers that may be trained by machine learning.

The threat management facility 100 may include an asset classification facility 160. The asset classification facility will discover the assets present in the enterprise facility 102. A compute instance such as any of the compute instances 10-26 described herein may be characterized as a stack of assets. The one level asset is an item of physical hardware. The compute instance may be, or may be implemented on physical hardware, and may have or may not have a hypervisor, or may be an asset managed by a hypervisor. The compute instance may have an operating system (e.g., Windows, MacOS, Linux, Android, iOS). The compute instance may have one or more layers of containers. The compute instance may have one or more applications, which may be native applications, e.g., for a physical asset or virtual machine, or running in containers within a computing environment on a physical asset or virtual machine, and those applications may link libraries or other code or the like, e.g., for a user interface, cryptography, communications, device drivers, mathematical or analytical functions and so forth. The stack may also interact with data. The stack may also or instead interact with users, and so users may be considered assets.

The threat management facility may include entity models 162. The entity models may be used, for example, to determine the events that are generated by assets. For example, some operating systems may provide useful information for detecting or identifying events. For examples, operating systems may provide process and usage information that accessed through an API. As another example, it may be possible to instrument certain containers to monitor the activity of applications running on them. As another example, entity models for users may define roles, groups, permitted activities and other attributes.

The event collection facility 164 may be used to collect events from any of a wide variety of sensors that may provide relevant events from an asset, such as sensors on any of the compute instances 10-26, the application protection facility 150, a cloud computing instance 109 and so on. The events that may be collected may be determined by the entity models. There may be a variety of events collected. Events may include, for example, events generated by the enterprise facility 102 or the compute instances 10-26, such as by monitoring streaming data through a gateway such as firewall 10 and wireless access point 11, monitoring activity of compute instances, monitoring stored files/data on the compute instances 10-26 such as desktop computers, laptop computers, other mobile computing devices, and cloud computing instances 19, 109. Events may range in granularity. An exemplary event may be communication of a specific packet over the network. Another exemplary event may be identification of an application that is communicating over a network.

The event logging facility 166 may be used to store events collected by the event collection facility 164. The event logging facility 166 may store collected events so that they can be accessed and analyzed by the analytics facility 168. Some events may be collected locally, and some events may be communicated to an event store in a central location or cloud facility. Events may be logged in any suitable format.

Events collected by the event logging facility 166 may be used by the analytics facility 168 to make inferences and observations about the events. These observations and inferences may be used as part of policies enforced by the security management facility Observations or inferences about events may also be logged by the event logging facility 166.

When a threat or other policy violation is detected by the security management facility 122, the remedial action facility 128 may be used to remediate the threat. Remedial action may take a variety of forms, non-limiting examples including collecting additional data about the threat, terminating or modifying an ongoing process or interaction, sending a warning to a user or administrator, downloading a data file with commands, definitions, instructions, or the like to remediate the threat, requesting additional information from the requesting device, such as the application that initiated the activity of interest, executing a program or application to remediate against a threat or violation, increasing telemetry or recording interactions for subsequent evaluation, (continuing to) block requests to a particular network location or locations, scanning a requesting application or device, quarantine of a requesting application or the device, isolation of the requesting application or the device, deployment of a sandbox, blocking access to resources, e.g., a USB port, or other remedial actions. More generally, the remedial action facility 122 may take any steps or deploy any measures suitable for addressing a detection of a threat, potential threat, policy violation or other event, code or activity that might compromise security of a computing instance 10-26 or the enterprise facility 102.

FIG. 2 depicts a block diagram of a threat management system 201 such as any of the threat management systems described herein, and including a cloud enterprise facility 280. The cloud enterprise facility 280 may include servers 284, 286, and a firewall 282. The servers 284, 286 on the cloud enterprise facility 280 may run one or more enterprise applications and make them available to the enterprise facilities 102 compute instances 10-26. It should be understood that there may be any number of servers 284, 286 and firewalls 282, as well as other compute instances in a given cloud enterprise facility 280. It also should be understood that a given enterprise facility may use both SaaS applications 156 and cloud enterprise facilities 280, or, for example, a SaaS application 156 may be deployed on a cloud enterprise facility 280. As such, the configurations in FIG. 1 and FIG. 2 are shown by way of examples and not exclusive alternatives.

Referring to FIG. 3, the asset classification facility 300 may discover, classify, and generate policies to evaluate the assets based on entity models. The asset classification facility may also determine asset configuration and state. In implementations, each compute instance may include a stack of assets that may include, for example, the physical device, and if present, hypervisor, operating system, containers, applications, libraries, and data. This is a generalized representation of compute instances, including as a few examples, personal computers, servers in a data center, mobile devices, or cloud instances running in EC2. Not all compute instances will have all of these types of assets. Different compute instances may have different assets. In implementations, users authorized to access the compute instance also may be considered an asset of a compute instance.

Asset information may be stored in an asset repository 310. The asset repository may be a database, file, or other data store. The asset repository 310 may hold a large number of assets, and so it may be suitable to be stored in a cloud infrastructure. The asset repository 310 may be distributed, and some assets may be stored locally and some assets may be stored in a cloud data store. In embodiments, the asset repository may include records for all of the recognized assets of all of the recognized compute instances in the enterprise facility.

The asset discovery facility 302 may discover the assets in the enterprise facility. In embodiments, discovery may be active or passive. Asset discovery may be performed by security agents running on compute instances and interrogating available assets. In some cases, asset discovery may be performed using APIs, for example, where agents are not available on a compute instance. Passive observation may also or instead be used to discover assets. For example, observation of network communication may reveal information about an asset. A goal of asset discovery may be to identify and characterize the compute instances and other associated assets present in the enterprise facility environment.

An asset classifier 304 may classify each asset. Each asset may fall into a set of asset classes. Asset classes may be determined through a combination of the attributes and the activity as the compute instances operate in the enterprise facility. Non-limiting examples of asset classes may include notebooks, servers, mobile devices, domain controllers, IoT devices, EC2 instances (running in cloud), Docker containers, etc., as well as the type, versions, and other features of the assets running on these assets.

Asset policies may be determined based on the classification of each asset. For example, assets on compute instances with agents may be subject to certain policy restrictions, and assets on compute instances without agents may be subject to different policy restrictions. The policies available for each asset may be provided to the policy management facility.

The configuration and state of assets may be determined. Again, active interrogation may be used as well as passive observation. The configuration and state of the assets may be stored in the asset repository. Changes to the operating environment may be observed. Configurations may be measured against benchmarks to verify a strong security configuration.

Data may be classified using techniques such as natural language processing, to understand the meaning of the data is and, for example, whether it represents high, medium, or low business impact. This information may be stored in the asset database.

Once classified, entity models may be used to define events that may be collected from or involving the assets. The event models define asset-specific attributes that may be collected. For example, event models related to a particular mobile device may include the device itself, the operating system, the amount of storage, and so forth. The operating system may have attributes such as the build version or the libraries used. The overall entity model will determine what information may be collected from sensors on the device, such as accelerometer, or GPS/location information. As another example, a domain controller may have available events such as specific event IDs, such as new processes that are created or activity that is happening on the Kerberos ticket-granting system. These events would be defined by the entity model for the domain controller.

Entity models may be continuously updated so that they are current. Examples of attributes that may be considered are: volumes of data, URLs visited, IP session partners, the file shares accessed, the processes started, usage times, and locations.

It should be noted that there may be a lot of information collected about compute instances and users, and this has privacy implications and scalability implications. Privacy may be addressed in some cases by user notifications and permissions, anonymization, tokenization, and encryption. It may also be useful to optimize the data, coalesce the data, compress the data, and serialize the data. Security features may be used to avoid abuse of APIs (e.g., authentication, replay protection, DoS protection). Performance optimizations, such as rate limiting, prioritization, and queue management may be used to improve scalability.

Referring to FIG. 4, an exemplary system demonstrating Sensors, Events, Analytics, and Response (SEAR) may be used on a compute instance 420 such as a managed device. The compute instance 420 may include sensors 431, 432, 433, 434 that produce data that are recognized as events according to the entity model. The sensors 431, 432, 433, 434 thus are sources of event information. The output of sensors 431, 432, 433, 444 may be objects 442 that are recognized as events 444. There may be multiple objects 442, 446 and events 444, 448 provided by a sensor. The events may be processed by a local event processing facility 454. The event processing may perform tokenizing and processing. Some events may be recognized and evaluated in real-time, other events may be evaluated in the context of other events. This may be stream or bulk processing. Events may have attributes (e.g., mandatory, optional (e.g., best effort), sensitive (tokenize it in local event store), or associated contextual information.

A local event recorder 450 may be part of the event logging facility. Some recorded events may be stored locally and some may be communicated to another compute instance, such as the cloud. Some events will all be sent in real time, some only stored locally (and should be retrievable). An event filter 462 may be used to parse the events. Local analytics 464 on a compute instance may be used to locally identify events of interest. A communication facility 460 will communicate events to a central event store, such as a cloud facility. Local enforcement 466 may be used to take steps in response to events, as determined by the policy management facility 466. In embodiments, events can have attributes (e.g., mandatory, optional (e.g., best effort), sensitive (e.g., tokenize it in local event store). Some events will all be sent in real time, some only stored locally (and should be retrievable).

A goal is to discover as much as we can about the assets in the enterprise, and reduce surprises, such as compute instances that network administrators are not aware of, or unpatched compute instances, or valuable data leaving the enterprise.

As one non-limiting example, static policies may be assigned to access of files and data. Events involving files and data may be observed by sensors, for example, in a file system filter, generating events. The events may be determined to be of interest based on the policies.

Referring to FIG. 5, centralized event collection 500 may be used to receive and store events from various compute instances. Events are received by event collection 562. Events may be stored in the event store 564, and also may be processed in real-time by the stream processing facility 566. The entity models 570 may be used by the analytics facility 568 to make observations and inferences based on the events.

In embodiments, events are continuously analyzed against a baseline. The baseline may be adjusted to account for normal behavior. Comparison to baselines may include looking for outliers and anomalies as well as impossible events. For example, if a user logs on from Germany and then logs in from San Francisco, that may be considered impossible. Comparisons may be made at different levels. For example, the entity may be compared to itself e.g., does this user on Monday compare to past activity. For example, the entity may be compared to its peer group, e.g., is a finance department member behaving similar to others. For example, the entity may be compared to other entities within the enterprise. For example, the entity may be compared to other users at similar enterprises in the same industry, or in the same location, as well as to the universe of all users.

Real-time and retrospective threat intelligence may also be included, as well as vulnerability information and patch information.

With a sufficient level of confidence in the inferences, active, adaptive responses may be taken. For example, policies may be updated to better fit the security profile to the environment that has been discovered and observed.

In embodiments, high-interaction interfaces allow an admin to interact with the event store 564 to better understand the assets in the enterprise facility and for specific purposes, such as threat hunting.

Referring to FIG. 6, a dynamic multifactor authenticator 600 may be used to dynamically evaluate the riskiness of a user, and provide authentication information that is based on the evaluation.

Compute instances 611, 612, 613 may connect to a SaaS application 630. The SaaS applications 630 each communication with an identity provider 620 (e.g., Azure Active Directory). The identity provider communicates with an identity provider interface, for example to provide multifactor authentication. For example, the IDP authentication interface 606 may send a text message or a notification to a mobile device that may be used as a requirement for authentication.

In embodiments, the hygiene, or riskiness of the user may be used as part of an authentication decision. An adaptive authentication facility 606 may evaluate any or all of entity state, risk score, value of data, consistency of user against the model, for example, using the analytics of FIG. 5. The adaptive authentication facility 606 may receive attestations about the state of integrity, or the health state of the user that is logging on. This may include the health of the device that the user is logging in on, as well as the overall risk score that the user brings. In embodiments, the authentication may be revoked if the risk score changes.

Referring to FIG. 7, a marketplace interface facility 700 is provided to allow other vendors, referred to as marketplace providers (MPP) 720 to offer functionality to customers via the threat management facility. For example, a MPP 720 may be granted access to event data or analytics data for an enterprise facility, and the MPP 720 may use that data for additional analytics or reporting. For example, a MPP 720 may provide additional sensor data, event data, asset classes, event models, agents (e.g., code that runs on endpoints) or other data, which may be used by the MPP 720, another third-party service, or the threat management facility (e.g., the policy management facility or the security facility) generally.

In embodiments, a MPP 720 can provide information about an asset that is otherwise not known by the system's sensors. For example, a MPP may be the vendor of a cloud service, and the MPP may use the marketplace interface facility 700 to provide events that are specific to the cloud service. Just as one example, the MPP may be a human resources system provider, and the marketplace interface 700 may be used to provide information about a user from the human resources system, such as that they are leaving the company shortly or have left the company. The MPP 720 also may provide rules to the policy management system to use the fact that a user is leaving the company to increase the scrutiny used to monitor data loss prevention.

The marketplace interface facility 700 generally controls what a given MPP is authorized to access and provide, and, with appropriate authorization, allows the MPP to participate in enforcement. A marketplace provider authentication facility 702 allows a marketplace provider 720 to access the marketplace interface 700. This may include a multifactor authentication and/or the use of certificates and encryption. A MPP filter facility 703 controls what a MPP has access to, based on the privileges of the provider and permissions given by an enterprise. While a MPP 720 may be vetted and considered trustworthy, appropriate access to security information may be controlled.

A MPP metering facility 704 measures usage of MPP services by enterprise facilities. There may be a variety of different subscription and payments models for MPP services, and the metering facility 704 may be used to address them. In some implementations, the MPP 720 has a separate billing relationship with the enterprise facility, and the MPP 720 pays the threat management facility for access. In implementations, the enterprise facility is billed by the threat management facility for the MPP 720 services along with other threat management software subscriptions or services, and the threat management facility pays the MPP 720 for additional services subscribed to by the customer. In some cases, MPP 720 services may be charged based on usage. In some cases, MPP 720 services may be charged for unlimited usage for certain enterprises, with access to specific services determined for billing purposes. The MPP billing facility 705 may collect and communicate billing information to the customer and/or the MPP, for example, based on the business model and the MPP metering 704.

An event logging interface 708 interacts with the event collection facility 764, event logging facility 766, and/or event analytics facility 768. For example, the MPP logging interface 708 may provide events to the event collection facility 764. The event logging interface may request events from the event logging facility 766, for example, to receive events from the event repository that may be used by the MPP 720. The event logging interface may receive observations or inferences from the event analytics facility 768, and pass those on to the MPP 720. The event logging interface 708 may provide observations or inferences to the event analytics facility 768 based on observations or inferences made by the MPP 720. Thus, the Event logging interface 708 allows the MPP 720 to participate in the event collection, logging, and analytics, for example, by logging additional events and/or interrogating the event repository.

The event logging interface 708 may include MPP specific code or data 710 that may be used for event collection 764, event logging 766, or event analytics 768. In implementations, the MPP specific code or data may run or may be accessed by the threat management facility to provide MPP specific functionality, such as to generate new policies, determine violations of policies, determine observations or inferences, etc. By running MPP specific code or data 710 on the threat management system, the threat management system may be able to integrate the MPP 720 functionality.

Referring to FIG. 8, a method for data loss prevention may be used to classify data within an enterprise, and use those classifications for analytics and response. In general, storage attributes of data stored a data store may be used to determine a recognition model. The recognition model then may be used to classify other data within the enterprise. Thus, more easily classified data may be used to classify other data in the enterprise. In embodiments, the data may be stored in the form of documents.

In embodiments, classifications for documents may be specified. Classifications may include, for example, a department associated with the documents, such as sales, finance, legal, and development, or groups within a department. Classifications may include, for example, an importance or value of the data, from the perspective of preventing loss of the data. For example, classifications may include highly confidential/high value, moderately confidential, moderate value, and non-confidential/low value. Classifications may include any suitable classification for a document that will enable decisions based on the classification.

In embodiments, storage attributes of a data store may be specified. For example, an enterprise may have one or more data stores such as a file server, a document management system, or an intranet or central data store such as Sharepoint. With reference to such data stores, storage attributes may include, for example, folder or directory names, document owners, groups with permissions to access, keywords assigned, and so on.

The classifications may be linked to storage attributes 801. For example, certain folders in a finance directory that are accessible only by the finance group may be classified as high value. Documents in folders in the finance directory that other departments are allowed to access may be classified as moderate value. Likewise, certain product management department documents with permissions assigned to a relatively small number of individuals may be considered high value. Other product management department documents with permissions assigned to a relatively large number of groups may be classified as low value. Classifications may be linked to storage attributes on a particular data store. For example, on a publicly accessible data store, all folders may be considered low value.

The documents in the data store may then be classified based on the linked classifications and storage attributes 802. For example, the data store may be scanned, and based on the storage attributes, a classification for documents may be determined.

A recognition model may be determined based on the documents in the data store 803. This may be accomplished in any suitable manner. In embodiments, attributes of documents are determined and stored in a feature vector. The feature vectors for documents in a classification may be clustered, and an average assigned to each cluster, thus generating a recognition model. In embodiments, signatures for portions of documents (e.g., using a sliding window) may be used as part of the feature vector. In embodiments, features such as entropy or complexity may be used as part of the feature vector. In embodiments, features of the documents, such as the type of document, the application(s) supported by the document, the level of permissions or encryption, and other features may be included in a feature vector.

It should be understood that any suitable recognition model may be used. For example, a neural network or other model may be trained using machine learning using, which may use inputs as described above for feature vectors. For example, signatures and rules may be used to determine document matches.

The recognition model may be used to classify additional documents within the enterprise 804. For example, there may be documents for which the storage attributes were not determinative. For example, there may be documents on users' local computers or in personal storage areas of a central data store. For example, there may be documents that are in email servers or on USB drives or other external drives. For example, there may be documents on cloud servers. The recognition model may be used to classify documents, for example, in the case of a feature vector model, by determining a feature vector for a given document or portion of a document, and matching it (e.g., an exact match or within a threshold distance) to one of the feature vectors. The classification of the exact match or sufficiently similar document may be assigned to the unclassified document.

The classification for a document may be stored, for example, in the asset repository 805, such as that described above. The classification for a document may be used, for example, for context when evaluating an action taken on a document.

Based on the classification, a protective action may be taken 806. For example, access to documents of high value may be restricted for users or processes that are evaluated as a risky or suspicious. For example, transfer of low value documents to a USB drive may be permitted, but transfer of high value documents may require additional verification or permissions, or may be prevented. For example, email attachments of high value documents outside of the enterprise may be required to be encrypted.

In embodiments, a confidence level in the classification may be used as part of the determination of the action. For example, if a document is an exact match to a classified document, confidence in the classification may be high. For example, if a document is a somewhat similar but not very close match to a classified document, confidence in the classification may be lower. In embodiments, a user may be given more leeway on restrictions with a lower confidence level.

FIG. 9 shows a flowchart of a method for threat detection with business impact scoring. In general, a computer model is created for automatically evaluating the business value of computing objects such as files and databases on an endpoint. This can be used to assess the potential business impact of a security compromise to an endpoint, or a process executing on an endpoint, in order to prioritize potential threats within an enterprise for human review and intervention. The business value may also or instead be used to train other models to recognize types of documents, to apply policies within an enterprise, or in any other manner consistent with the other techniques described herein.

As shown in step 902, the method 900 may include providing a valuation model for automatically estimating a business value of a file. Providing the valuation model may, for example, include training a machine learning algorithm to estimate the business value based on a training set of files each having a known business value. This may include training a machine learning model to recognize files with (known) high business value based on, e.g., ownership, authorship, content, access controls, and so forth. For example, the model may be trained to recognize credit card numbers, social security numbers, or other sensitive information including financial information, personal information, and other sensitive content within files indicative of actual or potential business value. The model may also or instead be trained to recognize potentially sensitive documents based on document type. For example, the model may be trained to classify documents as patent applications, resumes, financial statements, bank statements and so forth, with the corresponding classification used to assign an estimated value as appropriate.

This may also or instead include providing rules, regression models, heuristics, and so forth for identifying high business value files or otherwise estimating the value of files, data, content and the like. The valuation model may, for example, estimate value based on file location, based on an access control content, based on content, or based on any other context, usage, feature or combination of the foregoing. For example, the valuation model may estimate value based on one or more of encryption status, file type, file usage history, file creation date, file modification date, file content, and file author. More generally, this may include any human-interpretable features, or any other features useful for estimating business value, human-interpretable or otherwise, such as features independently identified by a clustering algorithm or other unsupervised machine learning technique.

These techniques may also or instead be used to estimate the business value of a machine or other domain based on the aggregated business value of files and the like within that estate. Thus while the description herein focuses on business value on a file-by-file basis, the method 900 contemplated herein may also or instead by used on a machine-by-machine basis or any other basis to estimate the business impact of potent threats.

As shown in step 904, the method 900 may include providing an integrative model, such as any of the integrative models described herein. For example, this may include creating an integrative model that evaluates a potential threat by a threat sample based on a combination of a first model configured to identify malicious code based on behavioral tags, a second model configured to identify malicious code based on an executable file path, and a third model configured to identify malicious code based on a Uniform Resource Locator within the threat sample. More generally, the integrative model may evaluate potential threats by computer objects based on one or more of file behavior, file signature, file path, Uniform Resource Locators accessed, or any other feature or combination of features suitable for assessing suspiciousness. The integrative model may also or instead include one or more machine learning models trained to recognize potentially malicious code based on a training set of known safe and known unsafe threat samples.

As shown in step 906, the method 900 may include identifying intermediate threats, e.g., with the integrative model. The one or more intermediate threats may include one or more computing objects with an objective score from the integrative model that are not within a predetermined confidence level of a safe score or a malicious score. The one or more computing objects may, for example, include a process, an executable, a file, and so forth. The one or more computing objects may also or instead include a registry of system settings, a secure kernel cache of process information, or any other data source, cache, resource or the like that might be usefully monitored for threat detection as contemplated herein.

Identifying intermediate threats may, for example, include configuring a threat management facility to evaluate new threat samples on endpoints within an enterprise network according to the integrative model based on, e.g., a filtered event stream as described herein, or any other technique or combination of techniques suitable for identifying code or other threat samples that cannot confidently be classified as safe or unsafe. Identifying intermediate threats may include evaluating new threat samples, such as by identifying one or more intermediate threats by any of the new threat samples that are not within a predetermined confidence level of safe code or malicious code according to the integrative model. It will be appreciated that, while an integrative model as contemplated herein is one useful model for identifying code that is not clearly safe or unsafe, other techniques for identifying intermediate threats may also or instead be used.

As shown in step 908, the method 900 may include estimating a business value of one or more intermediate threats with the valuation model described above. This may include generating an estimated dollar value of the contents of files accessed by a process or other computing object, or an estimated business impact of the public dissemination of information contained in such files. This may also or instead include generating a score otherwise indicative of business value based on any of the factors or features described herein.

As shown in step 910, the method 900 may include providing a user interface for presenting the one or more intermediate threats to a user for human evaluation. This may, for example, include any of the user interfaces described herein.

As shown in step 912, the method 900 may include ranking the one or more intermediate threats for presentation within the user interface, e.g., by ranking the intermediate threats with the valuation model described above. More generally, the intermediate threats may be ranked using any technique that reflects actual or potential business impact of the threat based on business value of affected data or compute instances, the likelihood or severity of the potential risk, or some combination of these. Thus in one aspect, ranking the intermediate threats may include ranking the intermediate threats based on a combination of a likelihood of maliciousness determined according to the integrative model and an estimated business value of associated files determined according to the valuation model.

As shown in step 914, the method 900 may include presenting a list of the one or more intermediate threats in the user interface. As discussed above, the list may be ranked according to a combination of an objective score of riskiness or suspiciousness (e.g., from the integrative model) and an objective score for the business value (e.g., from the valuation model).

As shown in step 916, the method 900 may include receiving a user disposition of an intermediate threat, for example using any of the techniques described herein. For example, this may include receiving a user-initiated remedial action for one of the intermediate threats in the user interface. This may also or instead include receiving a user risk assessment for one of the intermediate threats in the user interface, such as by explicitly categorizing the intermediate threat as safe, unsafe, unknown, or appropriate for increased monitoring. In another aspect, the method 900 may include remediating a risk to a high business value computing object in response to a user input in the user interface.

According to the foregoing, there is disclosed herein a system including a memory storing an integrative model and a valuation model, a threat management facility, and a web server. The integrative model may be configured to evaluate a potential threat by a threat sample based on a combination of a first model configured to identify malicious code based on behavioral tags, a second model configured to identify malicious code based on an executable file path, and a third model configured to identify malicious code based on a Uniform Resource Locator within the threat sample, and the valuation model configured to estimate a business impact of the potential threat based on an estimated business value of one or more files associated with the threat sample. The threat management facility may be configured to apply the integrative model to new threat samples and to identify intermediate threats that are not within a predetermined likelihood of being safe or unsafe. The web server may be configured to display a list of intermediate threats in a user interface, wherein the list of intermediate threats is ranked according to a combination of a first score from the integrative model and a second score from the valuation model. In one aspect, the threat management facility may be configured to remediate a risk to an endpoint in response to a user input received through the user interface.

FIG. 10 shows a system for enterprise document classification. In general, a collection of documents or other files and the like within an enterprise network may be labelled according to an enterprise document classification scheme using, e.g., any of the feature vectors, classification schemes, valuation techniques or the like described herein. Using this information, a recognition model such as a neural network or other suitable recognition model described herein can be used to automatically label other files throughout the enterprise network. In this manner, documents and the like throughout an enterprise can be automatically identified and managed according to features such as confidentiality, sensitivity, security risk, business value, and so forth.

As shown in FIG. 10, the system 1000 may generally include an enterprise network 1002 interconnecting a plurality of endpoints 1004, a threat management facility 1006, a training system 1008, and a labeling system 1010.

The enterprise network 1002 and the endpoints 1004 may be any of the networks and endpoints described herein. In general, each endpoint 1004 may store a number of documents or other files. For example, this may include documents such as word processing files, spreadsheets, HTML documents, images, audio files, video files, and so forth. This may also or instead include computer code such as source code, scripts, executable code, byte code and so forth. More generally, this may include any files suitable for classification and other processing as contemplated herein.

The threat management facility 1006 may be any of the threat management systems or the like described herein. The threat management facility 1006 may coordinate operation of the training system 1008 and the labeling system 1010, and may perform related functions such as storing the recognition model 1014. The threat management facility 1006 may also be configured to apply enterprise policies throughout the enterprise network 1002 based on the resulting, labeled documents along with any other information or context relevant to policy administration and enforcement, such as by applying an enterprise policy to each of the files 1012 based on a category identified in a label selected for each such file 1012 by the labeling system 1010.

In general, the training system 1008 may be configured to train the recognition model 1014 based on a manual or automatic selection of some of the files 1012 distributed throughout the enterprise. For example, the training system 1008 may be configured to receive a user selection of a plurality of files 1012 stored in the enterprise network 1002, to automatically or manually label each of the plurality of files according to a category selected from two or more predetermined categories, thereby providing a labeled data set, and to train the recognition model 1014, e.g., with machine learning or any other suitable techniques, to identify the category for a new file based on the plurality of files in the labeled data set.

The labeling system 1010 may apply the recognition model 1014 created by the training system 1008 to label other files throughout the enterprise network 1002. For example, the labeling system may be configured to locate other files 1012 in the enterprise network 1002 different than the plurality of files 1012, and to associate a label with each of the other files 1012 based upon the category selected by the recognition model for each of the other files 1012 from the two or more predetermined categories. The labels and categories may, for example, include any of the labels, categories, or other classification groups or schemes described herein.

FIG. 11 shows a flowchart of a method for enterprise document classification. In general, a system such as the system described above may be used to train a recognition model, and then apply the recognition model to label documents or other files throughout an enterprise network. An enterprise policy may then be applied based on (among other things), the label for each file.

As shown in step 1102, the method 1100 may begin with selecting files such as a plurality of documents stored within the enterprise network. More generally, the files may include one or more documents such as spreadsheets, word processing documents, presentations, or any of the other documents described herein. The files may also or instead include executables, source code, and other computer program code and the like. In another aspect, the files may include content such as electronic communications, electronic forms or other data that may be stored in a central repository such as a server, distributed among endpoints within the enterprise network, or some combination of these. Selecting may, for example, include automatically or manually selecting a representative group of files in a known directory, or owned by one or more users with known roles in the enterprise. In another aspect, this may include randomly selecting a number of files throughout the enterprise network.

As shown in step 1104, the method 1100 may include labeling the files. This may generally include manually labeling the files or automatically labeling the files. For example this may include explicitly labeling the selected files with a manual labeling process or an automatic or semi-automatic rule-based process or the like. Labeling may include labeling each of the plurality of files automatically (or manually) based on a file location. Labeling may also or instead include automatically (or manually) labeling each of the plurality of files with an organization role associated with a folder where the file is located, or an organization role of one or more users associated with the file. Labeling may also or instead include labeling each of the files based on permissions in a corresponding access control list.

For example, if a folder or a user is associated with a particular organization of an enterprise such as finance, legal, engineering and so forth, associated files may automatically be labeled accordingly. Thus in one aspect, labeling files may include automatically labeling each of a plurality of documents with a category for sensitivity according to a location, an access control list, and content of each of the plurality of documents, thereby providing a labeled data set for use by the recognition model. In another aspect, a machine learning engine or the like may be used to identify potentially misplaced or unrelated files based on, e.g., content, file type, ownership, etc. For example, if a computer automated design file were located in a directory dedicated to an accounting department, or if a document owned by an engineer or other technical personnel were located on an endpoint associated with a legal department employee, then this may indicate a misplace (either innocently or maliciously) document. A machine learning system, a rules-based system, an expert system or any other learning system or the like may be configured to recognize these outliers and exclude them from a training set, or to forward them for manual inspection prior to inclusion in a training set.

In another aspect, labeling the files includes labeling each of the plurality of files according to a category selected from two or more predetermined categories such as any of the classifications, categories or the like described herein. For example, the two or more predetermined categories may identify at least one of sensitivity, confidentiality, business value and the like. For example, sensitivity may indicate, e.g., whether a file contains personally identifying information or other personal data or the like that is not intended for public distribution or use. Confidentiality may relate to personally sensitive information, or may relate to information protected or intended to be kept secret by a corporate entity such as sales projections, customer lists, and so forth. Business value may be an estimated business value as describe above, any may be assigned as a continuous variable based on estimated value, or as a discrete category of business value such as high, medium or low. The predetermined categories may also or instead identify permissions for use of the plurality of files such as an access control list, permissions list, authorized user list, or the like. The two or more predetermined categories may also or instead identify organizational or departmental roles or the like associated with the files such as accounting, legal, engineering, management, human resources, and so forth. More generally any combination of these and/or any other categories or group of categories suitable for classifying files and applying an enterprise policy thereon may be used for categories as contemplated herein.

As shown in step 1106, the method 1100 may include configuring a recognition model to identify an appropriate one of the above categories or classifications to apply to a new file located within the enterprise network. For example, this may include configuring a recognition model, e.g., by training a machine learning model or the like, to identify the category from one of a number of predetermined categories for a new file based on a plurality of documents or other files in the labeled data set created in step 1104. For example, a machine learning system, a rules-based system, an expert system or any other learning system or the like may be configured to implement a given recognition model.

As shown in step 1108, the method 1100 may include locating other files such as documents in the enterprise network different than the plurality of files. In one aspect, locating other files includes locally searching for files with a local search agent on one or more endpoints within the enterprise network. Locating other files may also or instead include searching for files in a cloud storage facility for the enterprise network, or searching on shared storage resources such as a network directory, a shared folder, network attached storage, a storage area network, and so forth. Locating other files may also include querying enterprise-wide or endpoint-specific search engines, indices and the like, which may provide usefully information about the existence and location of files within an enterprise network.

As shown in step 1110, the method 1100 may include labeling files located in step 1108 using the recognition model configured in step 1106. For example, this may include associating a label with each of the other files located in step 1108 based upon the category selected for each of the other files from the two or more predetermined categories by the recognition model configured in step 1106. For example, this may include associating a label with each of the other files located in step 1108 based upon the category for sensitivity selected by the recognition model. As noted above, this may be based on any of a variety of file characteristics such as file location, file ownership, file function (e.g., finance, engineering, management, human resources, etc.), file permissions, directory ownership, directory permissions, and the like. This may also be based on other context such as file content, keywords (within files or in file metadata), and so forth.

As shown in step 1112, the method 1100 may include applying an enterprise policy based on the labels applied in step 1110, e.g., through a threat management facility or the like. For example, this may include applying an enterprise policy for sensitivity to each of the other files based upon the category identified in the label, wherein the enterprise policy controls at least one of file access and file movement. In general, this may include applying any suitable policy based on the category identified in such labels. The enterprise policy may, for example, control what users or user types can execute, open, edit, or delete a file, or the enterprise policy may control whether and where such files can be transmitted, either within the enterprise network or outside the enterprise network, or any combination of these. More generally, the enterprise policy may control file access and file movement, or any combination of these.

Where the categories include organizational roles, the enterprise policy may include one or more categories of authorized users associated with each of the two or more organizational roles. Similarly, the enterprise policy may include an access control list associated with each of the two or more organizational roles, e.g., to facilitate access to files on the basis or organization roles. The enterprise policy may also or instead include one or more use restrictions associated with at least one of the one or more organizational roles.

FIG. 12 shows a block diagram of a system for managing chain of custody for enterprise documents. In general, a ledger may store chain of custody information for files throughout an enterprise network. By identifying files with a homologous identifier such as a fuzzy hash that permits piecewise evaluation of similarity, the ledger can be used to track a chain of custody over a sequence of changes in content, ownership, and file properties. The ledger can be used, e.g., to evaluate trustworthiness of a file the first time it is encountered by an endpoint, or to apply enterprise policies based on trust.

In general, the system 1200 may include a plurality of endpoints 1204 storing a plurality of documents 1206, with an enterprise network 1208 interconnecting the plurality of endpoints 1204 in a communicating relationship. This may, for example, include any of the endpoints, documents (or other files or the like), and networks described herein.

A server 1210 may be coupled in a communicating relationship with the enterprise network 1208, and may store a ledger 1212 that contains a chain of custody for each of the plurality of documents 1206. In general, the chain of custody for each document 1206 may be formed of a record, or a number of records, in the ledger 1212 that includes contextual information such as a document owner, author or the like, along with one or more homologous identifiers such as fuzzy hashes or the like that permit identification of piecewise sets of identical bits (in an identical order) within the documents 1206. This facilitates file matching that is literally tied to file contents, while permitting an evaluation based on similarity rather than a strict identity of contents. This approach provides significant advantages over, e.g., cryptographic hashing which will typically yield a completely different hash when a single bit of a file is changed, and significant advantage over techniques using feature vectors or the like that might find similarity in the complete absence of substantially identical bit sequences within a file. Furthermore, suitable techniques for identifying homologous files are known in the art, such as fuzzy matching using, e.g., the open source ssdeep project, which provides a program for computing context triggered piecewise hashes, also referred to as fuzzy hashes.

Using these techniques, the server 1210, which may be a threat management facility or any other server contemplated herein, may be configured to respond to an information request containing a first fuzzy hash (or other homologous identifier), by matching the first fuzzy hash to one or more of the fuzzy hashes stored in the ledger and providing chain of custody information to a requestor for at least one of the plurality of documents corresponding to the one or more of the fuzzy hashes. The server 1210 may also or instead be configured to respond to an update request containing a second fuzzy hash by matching the second fuzzy hash to a matching one of the plurality of documents and adding the second fuzzy hash and related information to the chain of custody in the ledger for the matching one of the plurality of documents.

The server 1210 or some other threat management facility may also or instead be used to evaluate the trustworthiness of files based on similarity to other files in the ledger 1212 (along with the history of custody and modifications), and to apply an enterprise policy based on the assessment of trust.

FIG. 13 shows a method for managing chain of custody for documents in an enterprise network. This may particularly advantageous in contexts where the content of interest is hard to manage using digital rights management techniques, such as with configuration files or documents that regularly change over time. This may also be used in combination with the various sensors and events described herein to evaluate changes to files and the like in the context of other field information for a single endpoint or a number of endpoints on an enterprise network.

As shown in step 1302, the method 1300 may include creating a ledger containing document custody information. The ledger may initially be created through a background indexing process or the like that executes on endpoints within the enterprise network and provides initial source information, file metadata, and the like for local files, along with a homologous identifiers such as fuzzy hashes for evaluating similarity to other files. The data may be gathered for files distributed among endpoints within an enterprise network, or any other suitable domain, and aggregated within the ledger for use in subsequent chain of custody operations. In one aspect, the ledger may be periodically updated with new file scans. In another aspect, once an initial scan is completed, the ledger may be periodically updated as endpoints add, modify or delete files. This may also include performing a complete scan of each new endpoint that is added to the system, in which case each additional file may be checked against the ledger to see if the file, or a prior version of the file, already exists within the enterprise network.

The ledger may be stored in a database hosted at a threat management facility for the enterprise network, which may usefully provide a programmatic interface for submitting updates and queries to the ledger. In another aspect, the ledger may be stored in a cloud resource remotely accessible from the enterprise network. The ledger may also or instead include a distributed ledger, such as a blockchain, in which blocks of transactions are cryptographically secured and distributed throughout a network of participating devices, providing a useful combination of security, integrity, and redundancy. The chain of custody information stored in the ledger may be any information necessary or useful for tracking change to file custody and file contents as contemplated herein. For example, the chain of custody information may include an author and one or more users associated with a number of versions of a file. The chain of custody information may also or instead include at least one item that is cryptographically signed for authentication using a certificate from a trust authority such as a trusted platform module or a remote third party trust authority.

As shown in step 1304, the method 1300 may include generating a first fuzzy hash (or other homologous file identifier) for a file such as a document or other file for which custody information is to be requested. This may, for example, include calculating fuzzy hashes, e.g., for a file on an endpoint, over any suitable segment sizes, and with any suitable amount of overlap with adjacent segments. Thus, for example, segments may be relative large (e.g., megabytes) or small (e.g., kilobytes), and may include complete overlap and redundancy (e.g., 50% or more overlap with each adjacent segment), or no overlap. In general, a suitable segment size can be determined based on, e.g., typical files sizes of interest, processing capability, storage capacity, the desired sensitivity to file changes and so forth. In one aspect, this may include creating fuzzy hashes during the initial, indexing phase described above during which the ledger is created. In another aspect, this may occur when a file is opened, launched, or otherwise accessed for use on an endpoint. As depicted, step 1304 may include transmitting the first fuzzy hash to the ledger.

The fuzzy hash (and the other fuzzy hashes and homologous identifiers described herein) may, for example, include a context triggered piecewise hash or any other suitable identifier capable of uniquely identifying sequences of bits within a file or otherwise providing a computational basis for evaluating literal (e.g., bitwise) similarity between documents, or otherwise supporting tracking of changes in a manner suitable for use in a chain of custody method as described herein. The file may include any document, file or the like for which chain of custody information might usefully be tracked as described herein. For example, the file may include a document selected from a group consisting of a word processing document, a spreadsheet, an image, an audio file, and a video file. The file may also or instead include computer executable code selected from a group consisting of source code, byte code, compiled code, and script.

As shown in step 1306, the method 1300 may include requesting information such as chain of custody information for the file from the ledger. This may be based on the first fuzzy hash (or other homologous identifier) generated for the file in step 1304. The ledger, or a server such as a threat management facility responsible for maintaining and providing access to the ledger, may respond with chain of custody information based on this request. As depicted, step 1306 may also include receiving responsive chain of custody information from the ledger.

It will be understood that, in a ledger update process (as illustrated in the left hand column of FIG. 13), steps 1304 and 1306 may be omitted, and fuzzy hashes may simply be computed and transmitted to the ledger for archiving, although an update that occurs during a modification or the like may commonly result in fuzzy hashes that are added to a pre-existing chain of custody that includes previously generated fuzzy hashes.

As shown in step 1308, the method 1300 may include receiving a modification to the file. This may, for example, include a user edit, a system edit, or any other revision from any other entity or user within the enterprise network. This may include changes by an original author of a file, or modifications by a user different than the author of the file, or any combination of these.

As shown in step 1310, the method 1300 may include generating a second fuzzy hash for the file. A variety of events may be used to trigger generation of the second fuzzy hash. For example, the second fuzzy hash may be generated when the file is opened or launched on an endpoint, when the file is closed on the endpoint, when the file is saved, or based on some other file operation or the like. In another aspect, the second fuzzy hash may be generated on a scheduled basis, such as once per hour, once per day or the like. In another aspect, a combination of these techniques may be used. For example, hashes may be created and transmitted to the ledger frequently when a file is in use, and infrequently or never when a file is closed. Similarly, other security events such as a potential compromise or data leakage, may be used to trigger the creation of new fuzzy hashes for an endpoint, or for a directory or particular files on the endpoint. The frequency of hashing may also depend, e.g., on an estimated business value for a particular file or any other criteria indicative of commercial value, threat protection or the like.

As shown in step 1312, the method may include transmitting the second fuzzy hash to the ledger for inclusion in a chain of custody for the file. It will be understood that, while the method is describe in terms of a single fuzzy hash, and number of fuzzy hashes (or other homologous identifiers or the like) may be created for each file for which the chain of custody is being tracked in the ledger.

As shown in step 1314, the method 1300 may include generating fuzzy hashes or other homologous identifiers using any of the techniques described herein, such as those described in step 1304 above. As shown in step 1316, the method may include requesting chain of custody information from the ledger based on the hash using any of the techniques described herein, such as those described in step 1306 above.

As shown in step 1318, the method 1300 may include evaluating a trustworthiness of the file based on the chain of custody information received from the ledger. This may include an analysis of the amount and type of changes to the file, the entity or entities making the changes, and any other suitable contextual information such as the type of file (include classifications or categories such as those described above) and the number of different users making changes. For example, even a small number of changes by an unknown entity to a file from a trusted vendor may be suspicious, and lead to a determination of low trustworthiness. On the other hand, a large number of changes to a shared document in a shared folder by different users sharing a common department or organizational role may not be suspicious. Thus in one aspect, evaluating the trustworthiness of the file includes determining an amount of change to the file from one or more other files identified in the ledger. This may be determined based on a similarity of a homologous file identifier such as a fuzzy hash for the file to one or more other homologous file identifiers for the one or more other files identified in the ledger. In another aspect, evaluating the trustworthiness of the file may include evaluating a trustworthiness of one or more users associated with the file in the chain of custody information.

As shown in step 1320, the method 1300 may include applying an enterprise policy to the file based on the trustworthiness. The enterprise policy may include any rules or the like for using and managing files based on trustworthiness. For example, applying the enterprise policy may include blocking or allowing access to the file at an endpoint in the enterprise network. Applying the enterprise policy may include blocking or allowing a transmittal of the file through the enterprise network. In another aspect, applying the enterprise policy may include deploying a remedial measure based on a low trustworthiness of the file. For example, where the file is an untrustworthy executable, the file may be quarantined, and an endpoint hosting the file may be scanned, quarantined, or otherwise treated as a compromised network asset. In another aspect, where the nature of changes suggest high entropy suggestive of ransomware, suitable remediate measures may be taken to stop modifications to the file, locate an archival copy, and so forth. More generally, any pattern of modifications suggestive of malware deployment or other malicious activity may be used to trigger deployment of corresponding remedial measures. In general, a policy may be a static or dynamic policy, for example, as described herein.

In embodiments, combination of trustworthiness information, for example as determined from chain of custody information, and labels determined from file recognition or comparison, may be used to determine labels, policy, or control of files. The business value of the files also may be taken into account. For example, a high business value document belonging to accounting or management may be flagged if the chain of custody for a version of the document shows that it is being viewed by non-accounting and/or non-management personnel. In this manner, for example, activity such as inappropriate use or exfiltration of sensitive information such as financial information in violation of an enterprise policy may be detected when an unauthorized user appears in the chain of custody. It will also be understood that chain of custody information may generally be used prospectively, e.g., to determine whether a newly detected user/editor is appropriate for the corresponding content, or retrospectively, e.g., to draw policy or security conclusions based on a history of users and file usage. These techniques may also be used at varying levels of granularity, e.g., by using fuzzy hashes to identify whether the changes by a user affect sensitive information, or to estimate whether the amount of change appears consistent with the corresponding user. More generally, this disclosure contemplates any combination of the foregoing techniques useful for managing content distributed in an enterprise network and enforcing enterprise network policies, and all such combinations are intended to fall within the scope of this disclosure.

It will be appreciated that, while trustworthiness is used herein as a term of relative safety, any other metric or descriptor indicative of safety versus threat may also or instead be used. Thus, for example, the chain of custody information may be used to evaluate authenticity, data integrity, safety, and so forth, and any such metric or criterion may be used to support the application and enforcement of enterprise policies as contemplated herein.

The above systems, devices, methods, processes, and the like may be realized in hardware, software, or any combination of these suitable for a particular application. The hardware may include a general-purpose computer and/or dedicated computing device. This includes realization in one or more microprocessors, microcontrollers, embedded microcontrollers, programmable digital signal processors or other programmable devices or processing circuitry, along with internal and/or external memory. This may also, or instead, include one or more application specific integrated circuits, programmable gate arrays, programmable array logic components, or any other device or devices that may be configured to process electronic signals. It will further be appreciated that a realization of the processes or devices described above may include computer-executable code created using a structured programming language such as C, an object oriented programming language such as C++, or any other high-level or low-level programming language (including assembly languages, hardware description languages, and database programming languages and technologies) that may be stored, compiled or interpreted to run on one of the above devices, as well as heterogeneous combinations of processors, processor architectures, or combinations of different hardware and software. In another aspect, the methods may be embodied in systems that perform the steps thereof, and may be distributed across devices in a number of ways. At the same time, processing may be distributed across devices such as the various systems described above, or all of the functionality may be integrated into a dedicated, standalone device or other hardware. In another aspect, means for performing the steps associated with the processes described above may include any of the hardware and/or software described above. All such permutations and combinations are intended to fall within the scope of the present disclosure.

Embodiments disclosed herein may include computer program products comprising computer-executable code or computer-usable code that, when executing on one or more computing devices, performs any and/or all of the steps thereof. The code may be stored in a non-transitory fashion in a computer memory, which may be a memory from which the program executes (such as random-access memory associated with a processor), or a storage device such as a disk drive, flash memory or any other optical, electromagnetic, magnetic, infrared or other device or combination of devices. In another aspect, any of the systems and methods described above may be embodied in any suitable transmission or propagation medium carrying computer-executable code and/or any inputs or outputs from same.

It will be appreciated that the devices, systems, and methods described above are set forth by way of example and not of limitation. Absent an explicit indication to the contrary, the disclosed steps may be modified, supplemented, omitted, and/or re-ordered without departing from the scope of this disclosure. Numerous variations, additions, omissions, and other modifications will be apparent to one of ordinary skill in the art. In addition, the order or presentation of method steps in the description and drawings above is not intended to require this order of performing the recited steps unless a particular order is expressly required or otherwise clear from the context.

The method steps of the implementations described herein are intended to include any suitable method of causing such method steps to be performed, consistent with the patentability of the following claims, unless a different meaning is expressly provided or otherwise clear from the context. So, for example, performing the step of X includes any suitable method for causing another party such as a remote user, a remote processing resource (e.g., a server or cloud computer) or a machine to perform the step of X. Similarly, performing steps X, Y and Z may include any method of directing or controlling any combination of such other individuals or resources to perform steps X, Y and Z to obtain the benefit of such steps. Thus, method steps of the implementations described herein are intended to include any suitable method of causing one or more other parties or entities to perform the steps, consistent with the patentability of the following claims, unless a different meaning is expressly provided or otherwise clear from the context. Such parties or entities need not be under the direction or control of any other party or entity, and need not be located within a particular jurisdiction.

It should further be appreciated that the methods above are provided by way of example. Absent an explicit indication to the contrary, the disclosed steps may be modified, supplemented, omitted, and/or re-ordered without departing from the scope of this disclosure.

It will be appreciated that the methods and systems described above are set forth by way of example and not of limitation. Numerous variations, additions, omissions, and other modifications will be apparent to one of ordinary skill in the art. In addition, the order or presentation of method steps in the description and drawings above is not intended to require this order of performing the recited steps unless a particular order is expressly required or otherwise clear from the context. Thus, while particular embodiments have been shown and described, it will be apparent to those skilled in the art that various changes and modifications in form and details may be made therein without departing from the spirit and scope of this disclosure and are intended to form a part of the invention as defined by the following claims, which are to be interpreted in the broadest sense allowable by law. 

What is claimed is:
 1. A system comprising: a plurality of endpoints storing a plurality of documents; an enterprise network interconnecting the plurality of endpoints; and a server coupled in a communicating relationship with the enterprise network, the server storing a ledger with a chain of custody for each of the plurality of documents, the chain of custody for each one of the plurality of documents including one or more fuzzy hashes, each associated with a user of the one of the plurality of documents and contents of the one of the plurality of documents, the server configured to respond to an information request containing a first fuzzy hash, by matching the first fuzzy hash to one or more of the fuzzy hashes stored in the ledger and providing chain of custody information to a requestor for at least one of the plurality of documents corresponding to the one or more of the fuzzy hashes, the server further configured to respond to an update request containing a second fuzzy hash by matching the second fuzzy hash to a matching one of the plurality of documents and adding the second fuzzy hash and related information to the chain of custody in the ledger for the matching one of the plurality of documents.
 2. A method comprising: generating a first fuzzy hash for a file; requesting chain of custody information for the file from a ledger for an enterprise network based on the first fuzzy hash; receiving a modification to the file; generating a second fuzzy hash for the file; and transmitting the second fuzzy hash to the ledger for inclusion in a chain of custody for the file.
 3. The method of claim 2 wherein the file includes a document selected from a group consisting of a word processing document, a spreadsheet, an image, an audio file, and a video file.
 4. The method of claim 2 wherein the file includes computer executable code selected from a group consisting of source code, byte code, compiled code, and script.
 5. The method of claim 2 wherein receiving the modification includes receiving the modification from a user different than an author of the file.
 6. The method of claim 2 wherein the ledger is stored in database hosted at a threat management facility for the enterprise network.
 7. The method of claim 2 wherein the ledger is stored in a cloud resource remotely accessible from the enterprise network.
 8. The method of claim 2 wherein the ledger is a distributed ledger.
 9. The method of claim 2 wherein the chain of custody information includes an author and one or more users associated with a number of versions of the file.
 10. The method of claim 2 wherein the chain of custody information include at least one item that is cryptographically signed for authentication using a certificate from a trust authority.
 11. The method of claim 10 wherein the trust authority includes a trusted platform module or a remote third party trust authority.
 12. The method of claim 2 wherein the first fuzzy hash and the second fuzzy hash include context triggered piecewise hashes.
 13. A method comprising: generating a homologous file identifier for a file; requesting chain of custody information for the file from a ledger for an enterprise network based on the homologous file identifier; evaluating a trustworthiness of the file based on the chain of custody information; and applying an enterprise policy to the file based on the trustworthiness.
 14. The method of claim 13 wherein evaluating the trustworthiness of the file includes determining an amount of change to the file from one or more other files identified in the ledger based on a similarity of the homologous file identifier for the file to one or more other homologous file identifiers for the one or more other files identified in the ledger.
 15. The method of claim 13 wherein evaluating the trustworthiness of the file includes evaluating a trustworthiness of one or more users associated with the file in the chain of custody information.
 16. The method of claim 13 wherein the homologous file identifier includes a first fuzzy hash.
 17. The method of claim 16 further comprising receiving a modification to the file, generating a second fuzzy hash for the file, transmitting the second fuzzy hash to the ledger for inclusion in a chain of custody for the file.
 18. The method of claim 13 wherein applying the enterprise policy includes blocking or allowing access to the file at an endpoint in the enterprise network.
 19. The method of claim 13 wherein applying the enterprise policy includes blocking or allowing a transmittal of the file through the enterprise network.
 20. The method of claim 13 wherein applying the enterprise policy includes deploying a remedial measure based on a low trustworthiness of the file. 